package com.megatim.manuel.core.convert;

import org.apache.poi.xwpf.model.XWPFHeaderFooterPolicy;
import org.apache.poi.xwpf.usermodel.*;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTBookmark;

import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * Word .docx (XWPF) -> HTML, en conservant gras/italique/souligné/barré, couleur, police,
 * taille, alignement, titres (Heading/Titre 1..6 -> h1..h6), listes, tableaux, images, liens.
 */
public class DocxConverter extends AbstractHtmlConverter {

    public DocxConverter(Path outputDir) {
        super(outputDir);
    }

    @Override
    public ConversionResult convert(Path source, int order) throws IOException {
        String safe = safeBase(source, order);
        String htmlName = safe + ".html";

        List<Heading> headings = new ArrayList<>();
        List<Heading> figures = new ArrayList<>();
        List<Heading> landmarks = new ArrayList<>();
        Set<String> recordedFm = new HashSet<>();
        List<String> images = new ArrayList<>();
        StringBuilder body = new StringBuilder();
        int[] headingCounter = {0};
        int[] figureCounter = {0};
        int[] lmCounter = {0};
        int[] imgCounter = {0};

        try (FileInputStream fis = new FileInputStream(source.toFile());
             XWPFDocument doc = new XWPFDocument(fis)) {

            body.append(renderHeaderFooter(doc, true, images, imgCounter, safe));

            boolean inList = false;
            for (IBodyElement be : doc.getBodyElements()) {
                if (be instanceof XWPFParagraph) {
                    XWPFParagraph p = (XWPFParagraph) be;
                    boolean isList = p.getNumID() != null;
                    if (isList && !inList) { body.append("<ul>\n"); inList = true; }
                    if (!isList && inList) { body.append("</ul>\n"); inList = false; }
                    renderParagraph(doc, p, body, headings, headingCounter,
                            figures, figureCounter, images, imgCounter, safe, isList,
                            landmarks, recordedFm, lmCounter);
                } else if (be instanceof XWPFTable) {
                    if (inList) { body.append("</ul>\n"); inList = false; }
                    renderTable((XWPFTable) be, body, images, imgCounter, safe, landmarks, recordedFm, lmCounter);
                }
            }
            if (inList) body.append("</ul>\n");

            body.append(renderHeaderFooter(doc, false, images, imgCounter, safe));
        }

        // Titre du document = nom du fichier (identifie le document, sans le confondre avec son chapitre 1)
        String title = clean(stripExt(source.getFileName().toString()));

        writeHtml(htmlName, title, body.toString());
        ConversionResult result = new ConversionResult(htmlName, title, headings, images, figures);
        result.landmarks.addAll(landmarks);
        return result;
    }

    private void renderParagraph(XWPFDocument doc, XWPFParagraph p, StringBuilder out,
                                 List<Heading> headings, int[] hc,
                                 List<Heading> figures, int[] fc,
                                 List<String> images, int[] ic, String safe, boolean isList,
                                 List<Heading> landmarks, Set<String> recordedFm, int[] lc) throws IOException {
        int level = headingLevel(doc, p);
        String styleName = styleName(doc, p);
        String text = p.getText();
        // Signets Word (_Toc..., renvois) -> ancres HTML, pour rendre cliquables sommaire et références
        String marks = bookmarkAnchors(p);
        String inner = marks + renderRuns(p, images, ic, safe);
        String align = alignOf(p);

        // Pages liminaires (Résumé, Mots clés, Historique, Diffusion, Sommaire, Table des illustrations)
        String fmKey = FrontMatter.match(text);
        String lmAnchor = null;
        boolean excludeFromTree = false;
        if (fmKey != null && !recordedFm.contains(fmKey)) {
            recordedFm.add(fmKey);
            excludeFromTree = true;                       // évite le doublon dans le Sommaire
            lmAnchor = safe + "_lm" + (++lc[0]);
            if (FrontMatter.isEntry(fmKey)) landmarks.add(new Heading(FrontMatter.label(fmKey), 0, lmAnchor));
        }

        if (level > 0) {
            String anchor = lmAnchor != null ? lmAnchor : safe + "_h" + (++hc[0]);
            if (!excludeFromTree && !text.isBlank()) headings.add(new Heading(clean(text), level, anchor));
            out.append("<h").append(level).append(" id=\"").append(anchor).append("\"").append(align)
               .append(">").append(inner).append("</h").append(level).append(">\n");
        } else if (isCaptionStyle(p.getStyleID(), styleName)) {
            // Légende d'illustration -> entrée de la « Table des illustrations »
            String anchor = lmAnchor != null ? lmAnchor : safe + "_f" + (++fc[0]);
            if (lmAnchor == null && !text.isBlank()) figures.add(new Heading(clean(text), 1, anchor));
            out.append("<p class=\"caption\" id=\"").append(anchor).append("\"").append(align)
               .append(">").append(inner.isEmpty() ? "&nbsp;" : inner).append("</p>\n");
        } else if (isList) {
            String idAttr = lmAnchor != null ? " id=\"" + lmAnchor + "\"" : "";
            out.append("<li").append(idAttr).append(align).append(">").append(inner.isEmpty() ? "&nbsp;" : inner).append("</li>\n");
        } else if (lmAnchor != null) {
            out.append("<p id=\"").append(lmAnchor).append("\"").append(align).append(">")
               .append(inner.isEmpty() ? "&nbsp;" : inner).append("</p>\n");
        } else if (inner.trim().isEmpty()) {
            out.append("<p class=\"sp\">&nbsp;</p>\n");
        } else {
            out.append("<p").append(align).append(">").append(inner).append("</p>\n");
        }
    }

    /** Émet une ancre HTML invisible par signet Word du paragraphe (cible des liens internes). */
    private String bookmarkAnchors(XWPFParagraph p) {
        StringBuilder sb = new StringBuilder();
        for (CTBookmark b : p.getCTP().getBookmarkStartList()) {
            String name = b.getName();
            if (name == null || name.isEmpty() || "_GoBack".equals(name)) continue;
            sb.append("<a id=\"").append(esc(name)).append("\"></a>");
        }
        return sb.toString();
    }

    /** Nettoie un libellé de sommaire : espaces insécables, tabulations et espaces multiples. */
    private static String clean(String s) {
        if (s == null) return "";
        return s.replace(' ', ' ').replace(' ', ' ').replace(' ', ' ')
                .trim().replaceAll("\\s+", " ");
    }

    private boolean isCaptionStyle(String id, String name) {
        String s = ((id == null ? "" : id) + " " + (name == null ? "" : name)).toLowerCase();
        // Exclure les listes auto-générées (table des illustrations / table of figures)
        if (s.contains("table") || s.contains("toc") || s.contains("tabledesillustrations")) return false;
        return s.contains("caption") || s.contains("legend") || s.contains("lgende") || s.contains("légend");
    }

    private String styleName(XWPFDocument doc, XWPFParagraph p) {
        String id = p.getStyleID();
        if (id != null && doc.getStyles() != null) {
            XWPFStyle st = doc.getStyles().getStyle(id);
            if (st != null) return st.getName();
        }
        return null;
    }

    /** Rend l'en-tête (isHeader=true) ou le pied de page (false) par défaut du document. */
    private String renderHeaderFooter(XWPFDocument doc, boolean isHeader,
                                      List<String> images, int[] ic, String safe) throws IOException {
        XWPFHeaderFooterPolicy policy = doc.getHeaderFooterPolicy();
        if (policy == null) return "";
        XWPFHeaderFooter hf = isHeader ? policy.getDefaultHeader() : policy.getDefaultFooter();
        if (hf == null) return "";

        StringBuilder sb = new StringBuilder();
        for (XWPFParagraph p : hf.getParagraphs()) {
            String inner = renderRuns(p, images, ic, safe);
            if (!inner.trim().isEmpty()) {
                sb.append("<p").append(alignOf(p)).append(">").append(inner).append("</p>\n");
            }
        }
        if (sb.length() == 0) return "";
        String cls = isHeader ? "page-header" : "page-footer";
        return "<div class=\"" + cls + "\">\n" + sb + "</div>\n";
    }

    private void renderTable(XWPFTable t, StringBuilder out,
                             List<String> images, int[] ic, String safe,
                             List<Heading> landmarks, Set<String> recordedFm, int[] lc) throws IOException {
        out.append("<table class=\"wt\">\n");
        for (XWPFTableRow row : t.getRows()) {
            out.append("<tr>");
            for (XWPFTableCell cell : row.getTableCells()) {
                out.append("<td>");
                for (XWPFParagraph p : cell.getParagraphs()) {
                    String inner = renderRuns(p, images, ic, safe);
                    // Repère liminaire trouvé dans une cellule (page de garde sous forme de tableau)
                    String fmKey = FrontMatter.match(p.getText());
                    String id = "";
                    if (fmKey != null && !recordedFm.contains(fmKey)) {
                        recordedFm.add(fmKey);
                        String a = safe + "_lm" + (++lc[0]);
                        id = " id=\"" + a + "\"";
                        if (FrontMatter.isEntry(fmKey)) landmarks.add(new Heading(FrontMatter.label(fmKey), 0, a));
                    }
                    out.append("<div").append(id).append(alignOf(p)).append(">")
                       .append(inner.isEmpty() ? "&nbsp;" : inner).append("</div>");
                }
                out.append("</td>");
            }
            out.append("</tr>\n");
        }
        out.append("</table>\n");
    }

    private String renderRuns(XWPFParagraph p, List<String> images, int[] ic, String safe) throws IOException {
        StringBuilder sb = new StringBuilder();
        for (IRunElement ire : p.getIRuns()) {
            if (ire instanceof XWPFHyperlinkRun) {
                XWPFHyperlinkRun hr = (XWPFHyperlinkRun) ire;
                String content = renderRun(hr, images, ic, safe);
                XWPFHyperlink link = hr.getHyperlink(p.getDocument());
                String url = link != null ? link.getURL() : null;
                String anchor = hr.getAnchor();
                if (url != null && !url.isEmpty()) {
                    sb.append("<a href=\"").append(esc(url)).append("\">").append(content).append("</a>");
                } else if (anchor != null && !anchor.isEmpty()) {
                    // Lien interne vers un signet (sommaire, renvoi de pagination) -> ancre HTML
                    sb.append("<a href=\"#").append(esc(anchor)).append("\">").append(content).append("</a>");
                } else {
                    sb.append(content);
                }
            } else if (ire instanceof XWPFRun) {
                sb.append(renderRun((XWPFRun) ire, images, ic, safe));
            }
        }
        return sb.toString();
    }

    private String renderRun(XWPFRun r, List<String> images, int[] ic, String safe) throws IOException {
        StringBuilder style = new StringBuilder();

        String color = r.getColor();
        if (color != null && color.matches("[0-9A-Fa-f]{6}")) {
            style.append("color:#").append(color).append(';');
        }
        String font = r.getFontFamily();
        if (font != null && !font.isEmpty()) {
            style.append("font-family:'").append(font.replace("'", "")).append("';");
        }
        int size = r.getFontSize();
        if (size > 0) {
            style.append("font-size:").append(size).append("pt;");
        }

        UnderlinePatterns ul = r.getUnderline();
        boolean underline = ul != null && ul != UnderlinePatterns.NONE;
        boolean strike = r.isStrikeThrough();

        StringBuilder open = new StringBuilder();
        StringBuilder close = new StringBuilder();
        if (r.isBold())   { open.append("<b>");  close.insert(0, "</b>"); }
        if (r.isItalic()) { open.append("<i>");  close.insert(0, "</i>"); }
        if (underline)    { open.append("<u>");  close.insert(0, "</u>"); }
        if (strike)       { open.append("<s>");  close.insert(0, "</s>"); }

        StringBuilder imgs = new StringBuilder();
        for (XWPFPicture pic : r.getEmbeddedPictures()) {
            XWPFPictureData data = pic.getPictureData();
            if (data == null) continue;
            String ext = data.suggestFileExtension();
            if (ext == null || ext.isEmpty()) ext = "png";
            String name = writeImageBytes(safe, ++ic[0], ext, data.getData());
            images.add(name);
            imgs.append("<img src=\"").append(name).append("\" alt=\"\"/>");
        }

        String content = esc(r.text()) + imgs;
        if (content.isEmpty()) return "";

        String span = style.length() > 0
                ? "<span style=\"" + style + "\">" + content + "</span>"
                : content;
        return open + span + close.toString();
    }

    private int headingLevel(XWPFDocument doc, XWPFParagraph p) {
        String id = p.getStyleID();
        int lv = matchHeading(id);
        if (lv == 0) lv = matchHeading(styleName(doc, p));
        if (lv > 0) return lv;
        // Repli : niveau hiérarchique Word (outline level), porté par le paragraphe ou son style.
        // C'est ce qui alimente réellement le sommaire, même avec des styles de titres personnalisés.
        return outlineLevel(doc, p);
    }

    private int outlineLevel(XWPFDocument doc, XWPFParagraph p) {
        try {
            if (p.getCTP().isSetPPr() && p.getCTP().getPPr().isSetOutlineLvl()) {
                return clampOutline(p.getCTP().getPPr().getOutlineLvl().getVal().intValue());
            }
        } catch (Exception ignore) { /* pas de niveau direct */ }
        try {
            String id = p.getStyleID();
            if (id != null && doc.getStyles() != null) {
                XWPFStyle st = doc.getStyles().getStyle(id);
                if (st != null && st.getCTStyle() != null && st.getCTStyle().isSetPPr()
                        && st.getCTStyle().getPPr().isSetOutlineLvl()) {
                    return clampOutline(st.getCTStyle().getPPr().getOutlineLvl().getVal().intValue());
                }
            }
        } catch (Exception ignore) { /* pas de niveau dans le style */ }
        return 0;
    }

    /** outlineLvl Word : 0..8 = titres 1..9 (9 = corps de texte -> ignoré). On plafonne à h6. */
    private int clampOutline(int val) {
        if (val < 0 || val > 8) return 0;
        return Math.min(val + 1, 6);
    }

    private String alignOf(XWPFParagraph p) {
        ParagraphAlignment a = p.getAlignment();
        if (a == null) return "";
        switch (a) {
            case CENTER: return " style=\"text-align:center\"";
            case RIGHT:  return " style=\"text-align:right\"";
            case BOTH:   return " style=\"text-align:justify\"";
            default:     return "";
        }
    }
}